NASA Delays Endeavour Shuttle Launch to April 29

Space Shuttle Endeavour’s swan song will have to wait an extra 10 days, after a scheduling conflict with a Russian spacecraft forced NASA to delay the shuttle’s final launch from April 19 to April 29.

It’s a matter of who gets to go first, or actually how many get to go at the same time: In this case, an unmanned Russian cargo ship was due to dock with the International Space Station near the end of the month.

NASA didn’t want Endeavour dropping by while the Russian ship was there, and it sounds like the Russian mission couldn’t wait because it involves biological equipment that’s time-sensitive. NASA and Russian officials even looked into flying the Russian cargo into orbit on Endeavour, but threw in the towel after planning became too complex.

Endeavour’s due to deliver spare parts to the ISS during its two week mission. Also: Something called an Alpha Magnetic Spectrometer, basically a $2 billion particle physics experiment module designed to scour cosmic rays for unusual matter. The mission’s also helmed by Mark Kelly, spouse of Gabrielle Giffords, the Arizona Representative who was gravely wounded during a shooting on January 8, 2011.

Endeavour’s final voyage will be NASA’s penultimate shuttle mission. Closing the book on three decades of shuttle launches will be Shuttle Atlantis, which goes up sometime this summer.

Curiously, Endeavour’s Friday April 29 launch (at 3:47PM Eastern time) shares the day with Prince William and Kate Middleton’s sure to be silly-covered nuptials.